Spanish shipbuilder Navantia has successfully installed an air-independent propulsion (AIP) system on the Spanish Navy's S-80 submarine, S-83, at its shipyard in Cartagena. This innovative AIP system, known as BEST (bio-ethanol stealth technology), is based on hydrogen technology and allows the submarine to remain submerged for extended periods by recharging batteries while underwater. By utilizing a bioethanol reforming process to produce a hydrogen-rich stream for a fuel cell, the system enhances the submarine's stealth and operational capabilities. Navantia's third-generation AIP system is unique in that it generates hydrogen on demand, providing tactical advantages and improving strategic autonomy and deterrence for the Spanish Navy. The S-80 submarine, with an overall length of 80.8 meters and a submerged displacement of 3,000 tonnes, features advanced combat and platform control systems developed by Navantia. Additionally, it is equipped with a combat system, created in collaboration with Lockheed Martin, allowing it to launch land-attack tactical missiles, setting it apart from conventional submarines in NATO and the EU. The successful delivery of the first submarine in the S-80 series, Isaac Peral, marks a significant milestone for Navantia and its partners, showcasing their technological expertise in the global submarine market. The completion of the AIP system installation represents a leap forward in naval technology, enhancing Spain's naval capabilities and solidifying Navantia's position as a key player in the defense industry.